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| United States Patent |
5,712,244
|
|
Addison
, et al.
|
January 27, 1998
|
Rinse aid compositions comprising non-nitrogen-containing organs
diphosphonic acid, salt or complex thereof
Abstract
There is provided a rinse aid composition containing an organo diphosphonic
acid or its salts or complexes. The pH of said composition as a 1%
solution in distilled water at 20.degree. C. is preferably less than 7.
| Inventors:
|
Addison; Michael Crombie (Newcastle upon Tyne, GB2);
Jones; Lynda Anne (Newcastle upon Tyne, GB2);
Knox; Rhona Alexandra (Newcastle upon Tyne, GB2)
|
| Assignee:
|
Proctor & Gamble Company (Cincinnati, OH)
|
| Appl. No.:
|
704211 |
| Filed:
|
August 28, 1996 |
Foreign Application Priority Data
| Current U.S. Class: |
510/514; 510/421; 510/434; 510/436; 510/469; 510/476; 510/477 |
| Intern'l Class: |
C11D 003/36; C11D 001/66; C11D 003/37 |
| Field of Search: |
510/514,222,223,228,229,230,434,436,469,476,477,421
|
References Cited
U.S. Patent Documents
| 3687858 | Aug., 1972 | Geisler et al. | 252/156.
|
| 3784469 | Jan., 1974 | Krueger et al. | 252/180.
|
| 3791978 | Feb., 1974 | Krueger et al. | 252/180.
|
| 4704212 | Nov., 1987 | Schindler et al. | 252/8.
|
| 4810405 | Mar., 1989 | Waller et al. | 252/81.
|
| 4846993 | Jul., 1989 | Lentsch et al. | 252/95.
|
| 4935065 | Jun., 1990 | Bull | 134/22.
|
| 5118436 | Jun., 1992 | Aoyagi et al. | 252/186.
|
| 5281351 | Jan., 1994 | Romeo et al. | 252/99.
|
| 5382295 | Jan., 1995 | Aoki et al. | 134/2.
|
| 5545346 | Aug., 1996 | MacBeath et al. | 510/514.
|
| 5545352 | Aug., 1996 | Pike | 510/514.
|
| Foreign Patent Documents |
| 0 364 067 | Apr., 1990 | EP.
| |
| 4-332800 | Nov., 1992 | JP.
| |
| 4332800 | Nov., 1992 | JP.
| |
| 673 033 A5 | Jan., 1990 | CH.
| |
| 2203163 | Oct., 1988 | GB.
| |
| 2227021 | Jul., 1990 | GB.
| |
Other References
Chemical Abstract Accession No. 118:215376, for JP 4-332800, Nov. 19, 1992.
Derwent Abstract Accession No. 93-004727, for JP 4-332800, Nov. 19, 1992.
|
Primary Examiner: Hertzog; Ardith
Attorney, Agent or Firm: Patel; K. K., Zerby; K. W., Rasser; J. C.
Parent Case Text
This is a continuation of application Ser. No. 08/350,352, filed on Dec. 6,
1994, now abandoned.
Claims
We claim:
1. A rinse aid composition containing a non-nitrogen containing organo
diphosphonic acid or a salt or complex thereof, at least 5% by weight of a
surfactant system, and from 1% to 60% by weight of a carboxylate or
polycarboxylate detergent builder selected from the group consisting of
water soluble salts of lactic acid, glycolic acid and ethers thereof,
succinic acid, malonic acid, (ethylenedioxy) diacetic acid, maleic acid,
diglycolic acid, tartaric acid, tartronic acid, lamatic acid, citric acid,
aconitic acid, and citraconic acid, the pH of said composition as a 1%
solution in distilled water at 20.degree. C. being less than 7.
2. A rinse aid composition according to claim 1, wherein the detergent
builder is included in an amount of from 2% to 30% by weight.
3. A rinse aid composition according to claim 1, wherein the detergent
builder is included in an amount of from 2% to 20% by weight.
4. A rinse aid composition according to claim 1 containing an organic
polymer containing acrylic acid or its salts, having an average molecular
weight of less than 15,000.
5. A rinse aid composition according to claim 4 wherein said organic
polymer is a homopolymer having a molecular weight of from 500 to 12,000.
6. A rinse aid composition according to claim 4 wherein said organic
polymer is present at a level of from 0.005% to 20% by weight of the
composition.
7. A rinse aid composition according to claim 1 wherein said non-nitrogen
containing organo diphosphonic acid is a C.sub.1 to C.sub.4 diphosphonic
acid present at a level of from 0.005% to 20% by weight of the
composition.
8. A rinse aid composition according to claim 7 wherein said non-nitrogen
containing organo diphosphonic acid is ethane-1-hydroxy-1,1 diphosphonic
acid present at a level of from 0.1% to 15% by weight of the composition.
9. A rinse aid composition according to claim 1 containing from 0.005% to
20% by weight of a heavy metal ion sequestrant comprising at least one
organo aminophosphonate, nitrilotriacetic acid, polyaminocarboxylic acid
or iminodiacetic acid derivative.
10. A rinse aid composition according to claim 1 containing from 5% to 40%
by weight of the surfactant system.
11. A rinse aid composition according to claim 1, wherein the pH of said
composition as a 1% solution in distilled water at 20.degree. C. is from
0.5 to 6.5.
12. A rinse aid composition according to claim 1, wherein the pH of said
composition as a 1% solution in distilled water at 20.degree. C. is from
1.0 to 5.0.
13. A rinse aid composition according to claim 1, wherein the surfactant
system comprises at least one surfactant selected from the group
consisting of anionic, cationic, nonionic, ampholytic and zwitterionic
surfactants, and mixtures thereof.
14. A rinse aid composition containing a non-nitrogen containing organo
diphosphonic acid or a salt or complex thereof, a surfactant system
comprising at least one nonionic surfactant, and from 2% to 60% by weight
of a carboxylate or polycarboxylate detergent builder selected from the
group consisting of water soluble salts of lactic acid, glycolic acid and
ethers thereof, succinic acid, malonic acid, (ethylenedioxy) diacetic
acid, maleic acid, diglycolic acid, tartaric acid, tartronic acid, fumaric
acid, citric acid, aconitic acid, and citraconic acid, the pH of said
composition as a 1% solution in distilled water at 20.degree. C. being
less than 7.
15. A rinse aid composition according to claim 14, wherein the detergent
builder is included in an amount of from 2% to 30% by weight.
16. A rinse aid composition according to claim 14, wherein the detergent
builder is included in an amount of from 2% to 20% by weight.
17. A rinse aid composition according to claim 14 containing an organic
polymer containing acrylic acid or its salts, having an average molecular
weight of less than 15,000.
18. A rinse aid composition according to claim 17 wherein said organic
polymer is a homopolymer having a molecular weight of from 500 to 12,000.
19. A rinse aid composition according to claim 17 wherein said organic
polymer is present at a level of from 0.005% to 20% by weight of the
composition.
20. A rinse aid composition according to claim 14 wherein said non-nitrogen
containing organo diphosphonic acid is a C.sub.1 to C.sub.4 diphosphonic
acid present at a level of from 0.005% to 20% by weight of the
composition.
21. A rinse aid composition according to claim 20 wherein said non-nitrogen
containing organo diphosphonic acid is ethane-1-hydroxy-1,1 diphosphonic
acid present at a level of from 0.1% to 15% by weight of the composition.
22. A rinse aid composition according to claim 14, wherein the surfactant
system comprises at least one nonionic surfactant selected from the group
consisting of ethoxylated and propoxylated nonionic surfactants.
23. A rinse aid composition according to claim 14, wherein the surfactant
system is included in the composition in an amount of from 1% to 30% by
weight.
24. A rinse aid composition according to claim 14, wherein the surfactant
system is included in the composition in an mount of from 5% to 20% by
weight.
25. A rinse aid composition according to claim 14 containing from 0.005% to
20% by weight of a heavy metal ion sequestrant comprising at least one
organo aminophosphonate, nitrilotriacetic acid, polyaminocarboxylic acid
or iminodiacetic acid derivative.
26. A rinse aid composition according to claim 14 containing from 0.5% to
40% by weight of the surfactant system.
Description
TECHNICAL FIELD
The present invention relates to rinsing (rinse aid) compositions,
particularly acidic rinsing compositions containing an organo diphosphonic
acid crystal growth inhibitor component.
BACKGROUND OF THE INVENTION
Rinse aid compositions designed for use in automatic dishwasher machines
are well known. These compositions are added during the rinsing cycle of
the machine, separately from the detergent composition employed in the
main wash cycle(s). The ability to enhance rinsing, and in particular the
ability to prevent spot and film formation are common measures of rinse
aid performance.
Rinse aid compositions typically contain components such as nonionic
surfactants and/or hydrotropes which aid the wetting of the items in the
rinse, thereby improving the efficacy of the rinsing process. These
surfactants, and rinse aid compositions in general, are not designed for
the achievement of a primary soil removal purpose.
The general problem of the formation of deposits as spots and films on the
articles in the wash/rinse, and on the dishwasher machine parts is well
known in the art.
Whilst the general problem of deposit formation is known, a full
understanding of the many facets of the problem is however still an active
area of research.
A range of deposit types can be encountered. The redeposition of soils or
the breakdown products thereof, which have previously been removed from
the soiled tableware in the washload, provides one deposit type. Insoluble
salts such as calcium carbonate, calcium fatty acid salts (lime soaps), or
certain silicate salts are other common deposit types. Composite deposit
types are also common. Indeed, once an initial minor deposit forms it can
act as a "seeding centre" for the formation of a larger, possibly
composite, deposit structure.
Deposit formation can occur on a range of commonly encountered substrate
surfaces including plastic, glass, metal and china surfaces. Certain
deposit types however, show a greater propensity to deposit on certain
substrates. For example, lime soap deposit formation tends to be a
particular problem on plastic substrates.
The formation of insoluble carbonate, especially calcium carbonate,
deposits is a particular problem in the machine dishwashing art. There is
a general appreciation in the art, as represented for example by
EP-A-364,067 in the name of Clorox, CH-A-673,033 in the name of Cosmina,
and EP-A-551,670 in the name of Unilever, that calcium carbonate deposit
formation is a particular problem when non-phosphate containing detergent
formulations are employed. In general, this can be explained by the
slightly inferior builder capacity of the typically employed non-phosphate
builder systems in comparison to phosphate builder formulations. The
problem of calcium carbonate deposit formation is understood to be
especially apparent when these formulations contain a carbonate builder
component, as for example is essential to the compositions taught by
EP-A-364,067.
The Applicants have now found that the problem of CaCO.sub.3 deposit
formation can exist even in the absence of a carbonate builder component
in the machine dishwashing detergent formulation, and especially when that
formulation contains no phosphate builder components. It has also been
established that the problem is most apparent when highly alkaline
formulations, such as those of pH of 9.8 and above, are employed.
The naturally sourced, inlet water to the dishwasher machine can be a
sufficient source of Ca.sup.2+ and Mg.sup.2+ ions and CO.sub.3.sup.2-
/HCO.sub.3.sup.- ions to make deposit formation a problem. Whilst the salt
softening system, through which the inlet water will pass prior to entry
into the main cavity of the dishwasher machine, can be efficient at
removing the naturally present Ca.sup.2+ and Mg.sup.2+ ions it is
inefficient at removing the CO.sub.3.sup.2- /HCO.sub.3.sup.- ions which
therefore enter into the wash/rinse solution.
The Applicants have now established that both the levels of Ca.sup.2+
/Mg.sup.2+ hardness ions and the levels of CO.sub.3.sup.2-
/HCO.sub.3.sup.- ions in the wash/rinse water of the dishwasher machine
are factors controlling calcium carbonate deposit formation. Critical
levels of both components must be exceeded for deposit formation to occur.
These critical levels are to an extent interdependent. Thus, even in
wash/rinse solutions containing high levels of one component, deposit
formation will not occur in the absence of the critical level of the other
component.
The Applicants have further established that the formation of calcium
carbonate deposits occurs most noticeably in the rinse cycle of the
dishwasher machine. Deposit build up is most apparent on the heater
element of the dishwasher machine.
The Applicants have found that the problem of calcium carbonate deposit
formation may be effectively ameliorated by the inclusion of an organo
diphosphonic acid crystal growth inhibitor component into a rinse aid
formulation. Said rinse aid formulation is of particular utility when used
in combination with non-phosphate containing detergent formulations which,
as previously mentioned, tend to be more susceptible to the problem of
calcium carbonate deposit formation.
The Applicants have also found that carboxylates and polycarboxylates,
particularly citrates, are especially useful components of the
compositions of the invention because of their magnesium binding capacity
which tends to prevent the formation of insoluble magnesium salts, such as
magnesium silicate on the articles in the wash. Such polycarboxylates also
provide calcium binding capacity to the compositions, thus contributing
further to the prevention of the formation of calcium salt deposits.
The Applicants have also found that the more effective control of calcium
carbonate deposition can also lead to benefits in the prevention of the
formation of other deposit types, particularly lime soap deposits and
silicate deposits.
Lime soap deposits are most commonly encountered when the washload contains
fatty soils, which naturally contain levels of free fatty acids, and when
lipolytic enzymes are components of the formulation. Lipolytic enzymes
catalyse the degradation of fatty soils into free fatty acids and
glycerol. Silicate is a common component of machine dishwashing
formulations, where it is added for its china care capability. It is the
Applicant's finding that by preventing the formation of calcium carbonate
deposit "seeding centres", the build up of other deposit types from these
"seeding centres" is also prevented.
SUMMARY OF THE INVENTION
There is provided a rinse aid composition containing an organo diphosphonic
acid or its salts or complexes.
The pH of said composition as a 1% solution in distilled water at
20.degree. C. is preferably less than 7.
DETAILED DESCRIPTION OF THE INVENTION
Organo diphosphonic acid crystal growth inhibitor
The first essential component of the compositions in accord with the
invention is an organo diphosphonic acid or one of its salts or complexes.
The organo diphosphonic acid component is preferably present at a level of
from 0.005% to 20%, more preferably from 0.1% to 15%, most preferably from
0.5% to 10% by weight of the compositions.
By organo diphosphonic acid it is meant herein an organo diphosphonic acid
which does not contain nitrogen as part of its chemical structure. This
definition therefore excludes the organo aminophosphonates, which however
may be included in compositions of the invention as heavy metal ion
sequestrants.
The organo diphosphonic acid component may be present in its acid form or
in the form of one of its salts or complexes with a suitable counter
cation. Preferably any salts/complexes are water soluble, with the alkali
metal and alkaline earth metal salts/complexes being especially preferred.
The organo diphosphonic acid is preferably a C.sub.1 -C.sub.4 diphosphonic
acid, more preferably a C.sub.2 diphosphonic acid, such as ethylene
diphosphonic acid, or most preferably ethane 1-hydroxy-1,1-diphosphonic
acid (HEDP).
pH of the compositions
In a highly preferred aspect of the invention the compositions have a pH as
a 1% solution in distilled water at 20.degree. C. of less than 7,
preferably from 0.5 to 6.5, most preferably from 1.0 to 5.0.
The pH of the compositions may be adjusted by the use of various pH
adjusting agents. Preferred acidification agents include inorganic and
organic acids including, for example, carboxylate acids, such as citric
and succinic acids, polycarboxylate acids, such as polyacrylic acid, and
also acetic acid, boric acid, malonic acid, adipic acid, fumaric acid,
lactic acid, glycolic acid, tartaric acid, tartronic acid, maleic acid,
their derivatives and any mixtures of the foregoing. Bicarbonates,
particularly sodium bicarbonate, are useful pH adjusting agents herein. A
highly preferred acidification acid is citric acid which has the advantage
of providing builder capacity to the wash solution.
Heavy metal ion sequestrants
Heavy metal ion sequestrants are useful components herein. By heavy metal
ion sequestrants it is meant components which act to sequester (chelate)
heavy metal ions. These components may also have calcium and magnesium
chelation capacity, but preferentially they bind heavy metal ions such as
iron, manganese and copper.
Heavy metal ion sequestrants are preferably present at a level of from
0.005% to 20%, more preferably from 0.1% to 10%, most preferably from 0.2%
to 5% by weight of the compositions.
Heavy metal ion sequestrants, which are acidic in nature, having for
example phosphonic acid or carboxylic acid functionalities, may be present
either in their acid form or as a complex/salt with a suitable counter
cation such as an alkali or alkaline metal ion, ammonium, or substituted
ammonium ion, or any mixtures thereof. Preferably any salts/complexes are
water soluble. The molar ratio of said counter cation to the heavy metal
ion sequestrant is preferably at least 1:1.
Suitable heavy metal ion sequestrants for use herein include the organo
aminophosphonates, such as the amino alkylene poly (alkylene phosphonates)
and nitrilo trimethylene phosphonates. Preferred organo aminophosphonates
are diethylene triamine penta (methylene phosphonate) and hexamethylene
diamine tetra (methylene phosphonate).
Other suitable heavy metal ion sequestrants for use herein include
nitrilotriacetic acid and polyaminocarboxylic acids such as
ethylenediaminotetracetic acid, ethylenetriamine pentacetic acid, or
ethylenediamine disuccinic acid. Especially preferred is
ethylenediamine-N,N'-disuccinic acid (EDDS), most preferably present in
the form of its S,S isomer, which is preferred for its biodegradability
profile.
Still other suitable heavy metal ion sequestrants for use herein are
iminodiacetic acid derivatives such as 2-hydroxyethyl diacetic acid or
glyceryl imino diacetic acid, described in EPA 317 542 and EPA 399 133.
Low molecular weight acrylic acid containing organic polymer
The compositions in accord with the invention may contain as a preferred
component an organic polymer containing acrylic acid or its salts having
an average molecular weight of less than 15,000, hereinafter referred to
as low molecular weight acrylic acid containing polymer. Such low
molecular weight acrylic acid containing polymers may act as CaCO.sub.3
dispersants, and thus further enhance the CaCO.sub.3 deposition prevention
capability of the compositions herein.
The low molecular weight acrylic acid containing polymer has, an average
molecular weight of less than 15,000, preferably from 500 to 12,000, more
preferably from 1,500 to 10,000, most preferably from 2,500 to 9,000.
The low molecular weight acrylic acid containing organic polymer is
preferably present at a level of from 0.005% to 20%, more preferably from
0.1% to 10%, most preferably from 0.2% to 5% by weight of the
compositions.
The low molecular weight acrylic acid containing polymer may be either a
homopolymer or a copolymer including the essential acrylic acid or acrylic
acid salt monomer units. Copolymers may include essentially any suitable
other monomer units including modified acrylic, fumaric, maleic, itaconic,
aconitic, mesaconic, citraconic and methylenemalonic acid or their salts,
maleic anhydride, acrylamide, alkylene, vinylmethyl ether, styrene and any
mixtures thereof.
Preferred commercially available low molecular weight acrylic acid
containing homopolymers include Sokalan PA30, PA20, PA15 and PA10 by BASF
GmbH, and those sold under the tradename Acusol 45N by Rohm and Haas.
Preferred low molecular weight acrylic acid containing copolymers include
those which contain as monomer units: a) from about 90% to about 10%,
preferably from about 80% to about 20% by weight acrylic acid or its salts
and b) from about 10% to about 90%, preferably from about 20% to about 80%
by weight of a substituted acrylic monomer or its salts having the general
formula --›CR.sub.2 --CR.sub.1 (CO--O--R.sub.3)!-- wherein at least one of
the substituents R.sub.1, R.sub.2 or R.sub.3, preferably R.sub.1 or
R.sub.2 is a 1 to 4 carbon alkyl or hydroxyalkyl group, R.sub.1 or R.sub.2
can be a hydrogen and R.sub.3 can be a hydrogen or alkali metal salt. Most
preferred is a substituted acrylic monomer wherein R.sub.1 is methyl,
R.sub.2 is hydrogen. The most preferred copolymer of this type has a
molecular weight of 3500 and contains 60% to 80% by weight of acrylic acid
and 40% to 20% by weight of methyl acrylic acid.
Preferred commercially available low molecular weight acrylic acid
containing copolymers include those sold under the tradename Sokalan CP10
by BASF.
Other suitable polyacrylate/modified polyacrylate copolymers include those
copolymers of unsaturated aliphatic carboxylic acids disclosed in U.S.
Pat. Nos. 4,530,766, and 5,084,535 which have a molecular weight of less
than 15,000 in accordance with the invention.
Additional organic polymeric compound
Certain additional organic polymeric compounds may be added to the rinse
aid compositions of the invention, however, in certain cases their
presence is desirably minimized. By additional organic polymeric compounds
it is meant essentially any polymeric organic compounds commonly used as
dispersants, anti-redeposition and soil suspension agents in detergent
compositions, which do not fall within the definition of low molecular
weight acrylic acid containing polymers given hereinbefore.
Additional organic polymeric compound may be incorporated into the rinse
aid compositions of the invention at a level of from 0.05% to 30%,
preferably from 0.5% to 15%, most preferably from 1% to 10% by weight of
the compositions.
Examples of additional organic polymeric compounds whose presence is
desirably minimized, and which are preferably not present, include the
water soluble organic homo- or co-polymeric polycarboxylic acids or their
salts in which the polycarboxylic acid comprises at least two carboxyl
radicals separated from each other by not more than two carbon atoms.
Polymers of the latter type are disclosed in GB-A-1,596,756. Examples of
such salts are the copolymers of polyacrylate with maleic anhydride having
a molecular weight of from 20,000 to 150,000, especially about 40,000 to
80,000.
The polyamino compounds are useful herein including those derived from
aspartic acid such as those disclosed in EP-A-305282, EP-A-305283 and
EP-A-351629.
Other additional organic polymeric compounds suitable herein include
cellulose derivatives such as methylcellulose, carboxymethylcellulose and
hydroxyethylcellulose.
Further useful additional organic polymeric compounds are the polyethylene
glycols, particularly those of molecular weight 1000-10000, more
particularly 2000 to 8000 and most preferably about 4000.
Detergent Builder System
A highly preferred component of the rinsing compositions of the present
invention is a detergent builder system which is preferably present at a
level of from 0.5% to 60% by weight, more preferably from 1% to 30% by
weight, most preferably from 2% to 20% weight of the composition.
The detergent builder system is preferably water-soluble, and preferably
contains a carboxylate or polycarboxylate builder containing from one to
four carboxy groups, particularly selected from monomeric polycarboxylates
or their acid forms, homo or copolymeric polycarboxylic acids or their
salts in which the polycarboxylic acid comprises at least two carboxylic
radicals separated from each other by not more that two carbon atoms.
The detergent builder system can contain alkali metal, ammonium or
alkanonammonium salts of bicarbonates, borates, phosphates, and mixtures
of any of the foregoing.
Preferably, the detergent builder system contains no phosphate builder
compound.
Carboxylate or polycarboxylate builder
Suitable water-soluble monomeric or oligomeric carboxylate builders can be
selected from a wide range of compounds but such compounds preferably have
a first carboxyl logarithmic acidity/constant (pK.sub.1) of less than 9,
preferably of between 2 and 8.5, more preferably of between 4 and 7.5.
The carboxylate or polycarboxylate builder can be momomeric or oligomeric
in type although monomeric polycarboxylates are generally preferred for
reasons of cost and performance. Monomeric and oligomeric builders can be
selected from acyclic, alicyclic, heterocyclic and aromatic carboxylates.
Suitable carboxylates containing one carboxy group include the water
soluble salts of lactic acid, glycolic acid and ether derivatives thereof
as disclosed in Belgian Patent Nos. 831,368, 821,369 and 821,370.
Polycarboxylates containing two carboxy groups include the water-soluble
salts of succinic acid, malonic acid, (ethylenedioxy) diacetic acid,
maleic acid, diglycolic acid, tartaric acid, tartronic acid and fumaric
acid, as well as the ether carboxylates described in German
Offenlegenschrift 2,446,686, and 2,446,687 and U.S. Pat. No. 3,935,257 and
the sulfinyl carboxylates described in Belgian Patent No. 840,623.
Polycarboxylates containing three carboxy groups include, in particular,
water-soluble citrates, aconitrates and citraconates as well as succinate
derivatives such as the carboxymethyloxysuccinates described in British
Patent No. 1,379,241, lactoxysuccinates described in British Patent No.
1,389,732, and aminosuccinates described in Netherlands Application
7205873, and the oxypolycarboxylate materials such as 2-oxa-1,1,3-propane
tricarboxylates described in British Patent No. 1,387,447.
Polycarboxylates containing four carboxy groups include oxydisuccinates
disclosed in British Patent No. 1,261,829, 1,1,2,2-ethane
tetracarboxylates, 1,1,3,3-propane tetracarboxylates and 1,1,2,3-propane
tetracarboxylates. Polycarboxylates containing sulfo substituents include
the sulfosuccinate derivatives disclosed in British Patent Nos. 1,398,421
and 1,398,422 and in U.S. Pat. No. 3,936,448, and the sulfonated pyrolysed
citrates described in British Patent No. 1,439,000.
Alicyclic and heterocyclic polycarboxylates include
cyclopentane-cis,cis,cis-tetracarboxylates, cyclopentadienide
pentacarboxylates, 2,3,4,5-tetrahydrofuran-cis,cis,cis-tetracarboxylates,
2,5-tetrahydrofuran-cis-dicarboxylates,
2,2,5,5-tetrahydrofuran-tetracarboxylates,
1,2,3,4,5,6-hexane-hexacarboxylates and carboxymethyl derivatives of
polyhydric alcohols such as sorbitol, mannitol and xylitol. Aromatic
polycarboxylates include mellitic acid, pyromellitic acid and the phthalic
acid derivatives disclosed in British Patent No. 1,425,343.
Of the above, the preferred polycarboxylates are hydroxycarboxylates
containing up to three carboxy groups per molecule, more particularly
citrates, especially sodium citrate.
The parent acids of the monomeric or oligomeric polycarboxylate chelating
agents or mixtures thereof with their salts, e.g. citric acid or
citrate/citric acid mixtures are also contemplated as components of
builder systems of the compositions in accordance with the present
invention.
Phosphate builder compound
Specific examples of phosphate builders are the alkali metal
tripolyphosphates, sodium, potassium and ammonium pyrophosphate, sodium
and potassium and ammonium pyrophosphate, sodium and potassium
orthophosphate, sodium polymeta/phosphate in which the degree of
polymerization ranges from about 6 to 21, and salts of phytic acid.
Preferably, no phosphate builder compound is present.
Surfactant system
A highly preferred component of the compositions of the invention is a
surfactant system comprising surfactant selected from anionic, cationic,
nonionic, ampholytic and zwitterionic surfactants and mixtures thereof.
The surfactant system most preferably comprises low foaming nonionic
surfactant, selected for its wetting ability, preferably selected from
ethoxylated and/or propoxylated nonionic surfactants, more preferably
selected from nonionic ethoxylated/propoxylated fatty alcohol surfactants.
When the surfactant system comprises low foaming nonionic surfactant the
compositions preferably contain no additional suds suppressor components,
such as silicone suds suppressors as can be found in certain machine
dishwashing detergent compositions.
The surfactant system is typically present at a level of from 0.5% to 40%
by weight, more preferably 1% to 30% by weight, most preferably from 5% to
20% by weight of the compositions.
Anionic surfactant
Essentially any anionic surfactants useful for detersive purposes can be
included in the compositions. These can include salts (including, for
example, sodium, potassium, ammonium, and substituted ammonium salts such
as mono-, di- and triethanolamine salts) of the anionic sulfate,
sulfonate, carboxylate and sarcosinate surfactants.
Other anionic surfactants include the isethionates such as the acyl
isethionates, N-acyl taurates, fatty acid amides of methyl tauride, alkyl
succinates and sulfosuccinates, monoesters of sulfosuccinate (especially
saturated and unsaturated C.sub.12 -C.sub.18 monoesters) diesters of
sulfosuccinate (especially saturated and unsaturated C.sub.6 -C.sub.14
diesters), N-acyl sarcosinates. Resin acids and hydrogenated resin acids
are also suitable, such as rosin, hydrogenated rosin, and resin acids and
hydrogenated resin acids present in or derived from tallow oil.
Anionic sulfate surfactant
Anionic sulfate surfactants suitable for use herein include the linear and
branched primary alkyl sulfates, alkyl ethoxysulfates, fatty oleyl
glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, the C.sub.5
-C.sub.17 acyl-N-(C.sub.1 -C.sub.4 alkyl) and --N-(C.sub.1 -C.sub.2
hydroxyalkyl) glucamine sulfates, and sulfates of alkylpolysaccharides
such as the sulfates of alkylpolyglucoside (the nonionic nonsulfated
compounds being described herein).
Alkyl ethoxysulfate surfactants are preferably selected from the group
consisting of the C.sub.6 -C.sub.18 alkyl sulfates which have been
ethoxylated with from about 0.5 to about 20 moles of ethylene oxide per
molecule. More preferably, the alkyl ethoxysulfate surfactant is a C.sub.6
-C.sub.18 alkyl sulfate which has been ethoxylated with from about 0.5 to
about 20, preferably from about 0.5 to about 5, moles of ethylene oxide
per molecule.
Anionic sulfonate surfactant
Anionic sulfonate surfactants suitable for use herein include the salts of
C.sub.5 -C.sub.20 linear alkylbenzene sulfonates, alkyl ester sulfonates,
C.sub.6 -C.sub.22 primary or secondary alkane sulfonates, C.sub.6
-C.sub.24 olefin sulfonates, sulfonated polycarboxylic acids, alkyl
glycerol sulfonates, fatty acyl glycerol sulfonates, fatty oleyl glycerol
sulfonates, and any mixtures thereof.
Anionic carboxylate surfactant
Anionic carboxylate surfactants suitable for use herein include the alkyl
ethoxy carboxylates, the alkyl polyethoxy polycarboxylate surfactants and
the soaps (`alkyl carboxyls`), especially certain secondary soaps as
described herein.
Preferred alkyl ethoxy carboxylates for use herein include those with the
fomula RO(CH.sub.2 CH.sub.2 O).sub.x CH.sub.2 COO.sup.- M.sup.+ wherein R
is a C.sub.6 to C.sub.18 alkyl group, x ranges from 0 to 10, and the
ethoxylate distribution is such that, on a weight basis, the amount of
material where x is 0 is less than about 20%, and the amount of material
where x is greater than 7, is less than about 25%, the average x is from
about 2 to 4 when the average R is C.sub.13 or less, and the average x is
from about 3 to 10 when the average R is greater than C.sub.13, and M is a
cation, preferably chosen from alkali metal, alkaline earth metal,
ammonium, mono-, di-, and tri-ethanol-ammonium, most preferably from
sodium, potassium, ammonium and mixtures thereof with magnesium ions. The
preferred alkyl ethoxy carboxylates are those where R is a C.sub.12 to
C.sub.18 alkyl group.
Alkyl polyethoxy polycarboxylate surfactants suitable for use herein
include those having the formula RO--(CHR.sub.1 --CHR.sub.2 --O)--R.sub.3
wherein R is a C.sub.6 to C.sub.18 alkyl group, x is from 1 to 25, R.sub.1
and R.sub.2 are selected from the group consisting of hydrogen, methyl
acid radical, succinic acid radical, hydroxysuccinic acid radical, and
mixtures thereof, wherein at least one R.sub.1 or R.sub.2 is a succinic
acid radical or hydroxysuccinic acid radical, and R.sub.3 is selected from
the group consisting of hydrogen, substituted or unsubstituted hydrocarbon
having between 1 and 8 carbon atoms, and mixtures thereof.
Preferred soap surfactants are secondary soap surfactants which contain a
carboxyl unit connected to a secondary carbon. The secondary carbon can be
in a ring structure, e.g. as in p-octyl benzoic acid, or as in
alkyl-substituted cyclohexyl carboxylates. The secondary soap surfactants
should preferably contain no ether linkages, no ester linkages and no
hydroxyl groups. There should preferably be no nitrogen atoms in the
head-group (amphiphilic portion). The secondary soap surfactants usually
contain 11-13 total carbon atoms, although slightly more (e.g., up to 16)
can be tolerated, e.g. p-octyl benzoic acid.
The following general structures further illustrate some of the preferred
secondary soap surfactants:
A. A highly preferred class of secondary soaps comprises the secondary
carboxyl materials of the formula R.sup.3 CH(R.sub.4)COOM, wherein R.sup.3
is CH.sub.3 (CH.sub.2)x and R.sup.4 is CH.sub.3 (CH.sub.2)y, wherein y can
be 0 or an integer from 1 to 4, x is an integer from 4 to 10 and the sum
of (x+y) is 6-10, preferably 7-9, most preferably 8.
B. Another preferred class of secondary soaps comprises those carboxyl
compounds wherein the carboxyl substituent is on a ring hydrocarbyl unit,
i.e., secondary soaps of the formula R.sup.5 --R.sup.6 --COOM, wherein
R.sup.5 is C.sup.7 -C.sup.10, preferably C.sup.8 -C.sup.9, alkyl or
alkenyl and R.sup.6 is a ring structure, such as benzene, cyclopentane and
cyclohexane. (Note: R.sup.5 can be in the ortho, meta or para position
relative to the carboxyl on the ring.)
C. Still another preferred class of secondary soaps comprises secondary
carboxyl compounds of the formula CH.sub.3 (CHR).sub.k --CH.sub.2).sub.m
--(CHR).sub.n --CH(COOM)(CHR).sub.o --(CH2).sub.p --(CHR).sub.q
--CH.sub.3, wherein each R is C.sub.1 -C.sub.4 alkyl, wherein k, n, o, q
are integers in the range of 0-8, provided that the total number of carbon
atoms (including the carboxylate) is in the range of 10 to 18.
In each of the above formulas A, B and C, the species M can be any
suitable, especially water-solubilizing, counterion.
Especially preferred secondary soap surfactants for use herein are
water-soluble members selected from the group consisting of the
water-soluble salts of 2-methyl-1-undecanoic acid, 2-ethyl-1-decanoic
acid, 2-propyl-1-nonanoic acid, 2-butyl-1-octanoic acid and
2-pentyl-1-heptanoic acid.
Alkali metal sarcosinate surfactant
Other suitable anionic surfactants are the alkali metal sarcosinates of
formula R--CON (R.sup.1) CH.sub.2 COOM, wherein R is C.sub.5 -C.sub.17
linear or branched alkyl or alkenyl group, R.sup.1 is a C.sub.1 -C.sub.4
alkyl group and M is an alkali metal ion. Preferred examples are the
myristyl and oleyl methyl sarcosinates in the form of their sodium salts.
Nonionic surfactant
Essentially any nonanionic surfactants useful for detersive purposes can be
included in the compositions. Exemplary, non-limiting classes of useful
nonionic surfactants are listed below.
Nonionic polyhydroxy fatty acid amide surfactant
Polyhydroxy fatty acid amides suitable for use herein are those having the
structural formula R.sub.2 CONR.sub.1 Z wherein: R.sub.1 is H, C.sub.1
-C.sub.4 hydrocarbyl, 2-hydroxy ethyl, 2-hydroxy propyl, or a mixture
thereof, preferable C1-C4 alkyl, more preferably C.sub.1 or C.sub.2 alkyl,
most preferably C.sub.1 alkyl (i.e., methyl); and R.sub.2 is a C.sub.5
-C.sub.31 hydrocarbyl, preferably straight-chain C.sub.5 -C.sub.19 alkyl
or alkenyl, more preferably straight-chain C.sub.9 -C.sub.17 alkyl or
alkenyl, most preferably straight-chain C.sub.11 -C.sub.17 alkyl or
alkenyl, or mixture thereof; and Z is a polyhydroxyhydrocarbyl having a
linear hydrocarbyl chain with at least 3 hydroxyls directly connected to
the chain, or an alkoxylated derivative (preferably ethoxylated or
propoxylated) thereof. Z preferably will be derived from a reducing sugar
in a reductive amination reaction; more preferably Z is a glycityl.
Nonionic condensates of alkyl phenols
The polyethylene, polypropylene, and polybutylene oxide condensates of
alkyl phenols are suitable for use herein. In general, the polyethylene
oxide condensates are preferred. These compounds include the condensation
products of alkyl phenols having an alkyl group containing from about 6 to
about 18 carbon atoms in either a straight chain or branched chain
configuration with the alkylene oxide.
Nonionic ethoxylated alcohol surfactant
The alkyl ethoxylate condensation products of aliphatic alcohols with from
about 1 to about 25 moles of ethylene oxide are suitable for use herein.
The alkyl chain of the aliphatic alcohol can either be straight or
branched, primary or secondary, and generally contains from 6 to 22 carbon
atoms. Particularly preferred are the condensation products of alcohols
having an alkyl group containing from 8 to 20 carbon atoms with from about
2 to about 10 moles of ethylene oxide per mole of alcohol.
Nonionic ethoxylated/propoxylated fatty alcohol surfactant
The ethoxylated C.sub.6 -C.sub.18 fatty alcohols and C.sub.6 -C.sub.18
mixed ethoxylated/propoxylated fatty alcohols are highly preferred
surfactants for use herein, particularly where water soluble. Preferably
the ethoxylated fatty alcohols are the C.sub.10 -C.sub.18 ethoxylated
fatty alcohols with a degree of ethoxylation of from 3 to 50, most
preferably these are the C.sub.12 -C.sub.18 ethoxylated fatty alcohols
with a degree of ethoxylation from 3 to 40. Preferably the mixed
ethoxylated/propoxylated fatty alcohols have an alkyl chain length of from
10 to 18 carbon atoms, a degree of ethoxylation of from 3 to 30 and a
degree of propoxylation of from 1 to 10.
Nonionic EO/PO condensates with propylene glycol
The condensation products of ethylene oxide with a hydrophobic base formed
by the condensation of propylene oxide with propylene glycol are suitable
for use herein. The hydrophobic portion of these compounds preferably has
a molecular weight of from about 1500 to about 1800 and exhibits water
insolubility. Examples of compounds of this type include certain of the
commercially-available Pluronic.TM. surfactants, marketed by BASF.
Nonionic EO condensation products with propylene oxide/ethylene diamine
adducts
The condensation products of ethylene oxide with the product resulting from
the reaction of propylene oxide and ethylenediamine are suitable for use
herein. The hydrophobic moiety of these products consists of the reaction
product of ethylenediamine and excess propylene oxide, and generally has a
molecular weight of from about 2500 to about 3000. Examples of this type
of nonionic surfactant include certain of the commercially available
Tetronic.TM. compounds, marketed by BASF.
Nonionic alkylpolysaccharide surfactant
Suitable alkylpolysaccharides for use herein are disclosed in U.S. Pat. No.
4,565,647, Llenado, issued Jan. 21, 1986, having a hydrophobic group
containing from about 6 to about 30 carbon atoms, preferably from about 10
to about 16 carbon atoms and a polysaccharide, e.g., a polyglycoside,
hydrophilic group containing from about 1.3 to about 10, preferably from
about 1.3 to about 3, most preferably from about 1.3 to about 2.7
saccharide units. Any reducing saccharide containing 5 or 6 carbon atoms
can be used, e.g., glucose, galactose and galactosyl moieties can be
substituted for the glucosyl moieties. (Optionally the hydrophobic group
is attached at the 2-, 3-, 4-, etc. positions thus giving a glucose or
galactose as opposed to a glucoside or galactoside.) The intersaccharide
bonds can be, e.g., between the one position of the additional saccharide
units and the 2-, 3-, 4-, and/or 6- positions on the preceding saccharide
units.
The preferred alkylpolyglycosides have the formula
R.sup.2 O(C.sub.n H.sub.2n O)t(glycosyl).sub.x
wherein R2 is selected from the group consisting of alkyl, alkylphenyl,
hydroxyalkyl, hydroxyalkylphenyl, and mixtures thereof in which the alkyl
groups contain from 10 to 18, preferably from 12 to 14, carbon atoms; n is
2 or 3, preferably from about 1.3 to about 3, most preferably from about
1.3 to about 2.7. The glycosyl is preferably derived from glucose.
Nonionic fatty acid amide surfactant
Fatty acid amide surfactants suitable for use herein are those having the
formula:
##STR1##
wherein R.sup.6 is an alkyl group containing from 7 to 21, preferably from
9 to 17 carbon atoms and each R.sup.7 is selected from the group
consisting of hydrogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4
hydroxyalkyl, and --(C.sub.2 H.sub.4 O).sub.x H, where x is in the range
of from 1 to 3.
Amphoteric surfactant
Suitable amphoteric surfactants for use herein include the amine oxide
surfactants and the alkyl amphocarboxylic acids.
A suitable example of an alkyl amphodicarboxylic acid for use herein is
Miranol(TM) C2M Conc. manufactured by Miranol, Inc., Dayton, N.J.
Amine Oxide surfactant
Amine oxides useful in the present invention include those compounds having
the formula:
##STR2##
wherein R.sup.3 is selected from an alkyl, hydroxyalkyl, acylamidopropoyl
and alkyl phenyl group, or mixtures thereof, containing from 8 to 26
carbon atoms, preferably 8 to 18 carbon atoms; R.sup.4 is an alkylene or
hydroxyalkylene group containing from 2 to 3 carbon atoms, preferably 2
carbon atoms, or mixtures thereof; x is from 0 to 5, preferably from 0 to
3; and each R.sup.5 is an alkyl or hydyroxyalkyl group containing from 1
to 3, preferably from 1 to 2 carbon atoms, or a polyethylene oxide group
containing from 1 to 3, preferable 1, ethylene oxide groups. The R.sup.5
groups can be attached to each other, e.g., through an oxygen or nitrogen
atom, to form a ring structure.
These amine oxide surfactants in particular include C.sub.10 -C.sub.18
alkyl dimethyl amine oxides and C.sub.8 -C.sub.18 alkoxy ethyl
dihydroxyethyl amine oxides. Examples of such materials include
dimethyloctylamine oxide, diethyldecylamine oxide,
bis-(2-hydroxyethyl)dodecylamine oxide, dimethyldodecylamine oxide,
dipropyltetradecylamine oxide, methylethylhexadecylamine oxide,
dodecylamidopropyl dimethylamine oxide, cetyl dimethylamine oxide, stearyl
dimethylamine oxide, tallow dimethylamine oxide and
dimethyl-2-hydroxyoctadecylamine oxide. Preferred are C.sub.10 -C.sub.18
alkyl dimethylamine oxide, and C.sub.10-18 acylamido alkyl dimethylamine
oxide.
Zwitterionic surfactant
Zwitterionic surfactants can also be incorporated into the detergent
compositions hereof. These surfactants can be broadly described as
derivatives of secondary and tertiary amines, derivatives of heterocyclic
secondary and tertiary amines, or derivatives of quaternary ammonium,
quaternary phosphonium or tertiary sulfonium compounds. Betaine and
sultaine surfactants are exemplary zwitterionic surfactants for use
herein.
Betaine surfactant
The betaines useful herein are those compounds having the formula
R(R').sub.2 N.sup.+ R.sup.2 COO.sup.- wherein R is a C.sub.6 -C.sub.18
hydrocarbyl group, preferably a C.sub.10 -C.sub.16 alkyl group or
C.sub.10-16 acylamido alkyl group, each R.sup.1 is typically C.sub.1
-C.sub.3 alkyl, preferably methyl,m and R.sup.2 is a C.sub.1 -C.sub.5
hydrocarbyl group, preferably a C.sub.1 -C.sub.3 alkylene group, more
preferably a C.sub.1 -C.sub.2 alkylene group. Examples of suitable
betaines include coconut acylamidopropyldimethyl betaine; hexadecyl
dimethyl betaine; C.sub.12-14 acylamidopropylbetaine; C.sub.8-14
acylamidohexyldiethyl betaine; 4›C.sub.14-16
acylmethylamidodiethylammonio!-1-carboxybutane; C.sub.16-18
acylamidodimethylbetaine; C.sub.12-16 acylamidopentanediethyl-betaine;
›C.sub.12-16 acylmethylamidodimethylbetaine. Preferred betaines are
C.sub.12-18 dimethyl-ammonio hexanoate and the C.sub.10-18
acylamidopropane (or ethane) dimethyl (or diethyl) betaines. Complex
betaine surfactants are also suitable for use herein.
Sultaine surfactant
The sultaines useful herein are those compounds having the formula
(R(R.sup.1).sub.2 N.sup.+ R.sup.2 SO.sub.3.sup.- wherein R is a C.sub.6
-C.sub.18 hydrocarbyl group, preferably a C.sub.10 -C.sub.16 alkyl group,
more preferably a C.sub.12 -C.sub.13 alkyl group, each R.sup.1 is
typically C.sub.1 -C.sub.3 alkyl, preferably methyl, and R.sup.2 is a
C.sub.1 -C.sub.6 hydrocarbyl group, preferably a C.sub.1 -C.sub.3 alkylene
or, preferably, hydroxyalkylene group.
Ampholytic surfactant
Ampholytic surfactants can be incorporated into the detergent compositions
herein. These surfactants can be broadly described as aliphatic
derivatives of secondary or tertiary amines, or aliphatic derivatives of
heterocyclic secondary and tertiary amines in which the aliphatic radical
can be straight chain or branched.
Cationic surfactants
Cationic surfactants can also be used in the compositions herein. Suitable
cationic surfactants include the quaternary ammonium surfactants selected
from mono C.sub.6 -C.sub.16, preferably C.sub.6 -C.sub.10 N-alkyl or
alkenyl ammonium surfactants wherein the remaining N positions are
substituted by methyl, hydroxyethyl or hydroxypropyl groups.
Lime soap dispersant compound
The compositions of the invention may contain a lime soap dispersant
compound, which has a lime soap dispersing power (LSDP), as defined
hereinafter of no more than 8, preferably no more than 7, most preferably
no more than 6. The lime soap dispersant compound is preferably present at
a level of from 0.1% to 40% by weight, more preferably 1% to 20% by
weight, most preferably from 2% to 10% by weight of the compositions.
A lime soap dispersant is a material that prevents the precipitation of
alkali metal, ammonium or amine salts of fatty acids by calcium or
magnesium ions. A numerical measure of the effectiveness of a lime soap
dispersant is given by the lime soap dispersing power (LSDP) which is
determined using the lime soap dispersion test as described in an article
by H. C. Borghetty and C. A. Bergman, J. Am. Oil. Chem. Soc., volume 27,
pages 88-90, (1950). This lime soap dispersion test method is widely used
by practitioners in this art field being referred to , for example, in the
following review articles; W. N. Linfield, Surfactant Science Series,
Volume 7, p3; W. N. Linfield, Tenside Surf. Det. , Volume 27,
pages159-161, (1990); and M. K. Nagarajan, W. F. Masler, Cosmetics and
Toiletries, Volume 104, pages 71-73, (1989). The LSDP is the % weight
ratio of dispersing agent to sodium oleate required to disperse the lime
soap deposits formed by 0.025g of sodium oleate in 30 ml of water of 333
ppm CaCO.sub.3 (Ca:Mg=3:2) equivalent hardness.
Polymeric lime soap dispersants suitable for use herein are described in
the article by M. K. Nagarajan and W. F. Masler, to be found in Cosmetics
and Toiletries, Volume 104, pages 71-73, (1989). Examples of such
polymeric lime soap dispersants include certain water-soluble salts of
copolymers of acrylic acid, methacrylic acid or mixtures thereof, and an
acrylamide or substituted acrylamide, where such polymers typically have a
molecular weight of from 5,000 to 20,000.
Surfactants having good lime soap dispersant capability will include
certain amine oxides, betaines, sulfobetaines, alkyl ethoxysulfates and
ethoxylated alcohols.
Exemplary surfactants having a LSDP of no more than 8 for use in accord
with the invention include C.sub.16 -C.sub.18 dimethyl amine oxide,
C.sub.12 -C.sub.18 alkyl ethoxysulfates with an average degree of
ethoxylation of from 1-5, particularly C.sub.12 -C.sub.15 alkyl
ethoxysulfate surfactant with a degree of ethoxylation of about 3
(LSDP=4), and the C.sub.13 -C.sub.15 ethoxylated alcohols with an average
degree of ethoxylation of either 12 (LSDP=6) or 30, sold under the trade
names Lutensol A012 and Lutensol A030 respectively, by BASF GmbH.
Solvent
The compositions of the invention may contain organic solvents,
particularly when formulated as liquids or gels. The compositions in
accord with the invention preferably contain a solvent system present at
levels of from 1% to 30% by weight, preferably from 3% to 25% by weight,
more preferably form 5% to 20% by weight of the composition. The solvent
system may be a mono, or mixed solvent system. Preferably, at least the
major component of the solvent system is of low volatility.
Suitable organic solvent for use herein has the general formula RO(CH.sub.2
C(Me)HO).sub.n H, wherein R is an alkyl, alkenyl, or alkyl aryl group
having from 1 to 8 carbon atoms, and n is an integer from 1 to 4.
Preferably, R is an alkyl group containing 1 to 4 carbon atoms, and n is 1
or 2. Especially preferred R groups are n-butyl or isobutyl. Preferred
solvents of this type are 1-n-butoxypropane-2-ol (n=1); and
1(2-n-butoxy-1-methylethoxy)propane-2-ol (n=2), and mixtures thereof.
Other solvents useful herein include the water soluble CARBITOL solvents or
water-soluble CELLOSOLVE solvents. Water-soluble CARBITOL solvents are
compounds of the 2-(2 alkoxyethoxy) ethanol class wherein the alkoxy group
is derived from ethyl, propyl or butyl; a preferred water-soluble carbitol
is 2-(2-butoxyethoxy) ethanol also known as butyl carbitol. Water-soluble
CELLOSOLVE solvents are compounds of the 2-alkoxyethoxy ethanol class,
with 2-butoxyethoxyethanol being preferred.
Other suitable solvents are benzyl alcohol, and diols such as
2-ethyl-1,3-hexanediol and 2,2,4-trimethl-1,3-pentanediol.
The low molecular weight, water-soluble, liquid polyethylene glycols are
also suitable solvents for use herein.
The alkane mono and diols, especially the C.sub.1 -C.sub.6 alkane mono and
diols are suitable for use herein. C.sub.1 -C.sub.4 monohydric alcohols
(eg: ethanol, propanol, isopropanol, butanol and mixtures thereof) are
preferred, with ethanol particularly preferred. The C.sub.1 -C.sub.4
dihydric alcohols, including propylene glycol, are also preferred.
Hydrotropes
Hydrotrope may be added to the compositions in accord with the present
invention, and is typically present at levels of from 0.5% to 20%,
preferably from 1% to 10%, by weight.
Useful hydrotropes include sodium, potassium, and ammonium xylene
sulfonates, sodium, potassium, and ammonium toluene sulfonate, sodium
potassium and ammonium cumene sulfonate, and mixtures thereof.
Optional detergent components
Whilst the rinse aid compositions of the invention preferably contain
optional detergent components selected from a detergent builder system, a
surfactant system, a solvent, a hydrotrope, a pH adjusting agent and an
organic polymeric compound, as described herein, they preferably do not
contain cleaning components more typically found in machine dishwashing
detergent compositions, such as bleaching species and enzymes.
Form of the compositions
The compositions of the invention can be formulated in any desirable form
such as powders, granulates, pastes, liquids and gels. Liquid compositions
are most preferred.
Liquid compositions
The compositions of the present invention are preferably formulated as
liquid compositions which typically comprise from 94% to 35% by weight,
preferably from 90% to 40% by weight, most preferably from 80% to 50% by
weight of a liquid carrier, e.g., water, preferably a mixture of water and
organic solvent.
Gel compositions
Gel compositions are typically formulated with polyakenyl polyether having
a molecular weight of from about 750,000 to about 4,000,000.
Machine dishwashing method
The rinse aid compositions in accord with the present invention may be used
in essntially any conventional machine dishwashing method of the
conventional type performed using a dishwasher machine, which may be
selected from any of those commonly available on the market.
The machine dishwashing method typically comprises treating soiled
articles, such as crockery, glassware, hollowware and cutlery, with an
aqueous liquid having dissolved or dispersed therein an effective amount
of detergent composition. By an effective amount of detergent composition
it is generally meant from 8 g to 60 g of detergent composition per wash,
dissolved or dispersed in a wash solution volume of from 3 to 10 liters,
as are typical product dosages employed in conventional machine
dishwashing methods. The wash temperature may be in the range 40.degree.
C. to 65.degree. C. as commonly is employed in such processes. The rinse
aid composition is typically employed at levels of from 0.5g to 10g of
rinse aid composition per rinse cycle.
Wash/rinse Solution
It has been found that calcium carbonate deposits are most likely to be a
problem when certain threshold limits of both Ca.sup.2+ /Mg.sup.2+
hardness and CO.sub.3.sup.2- /HCO.sub.3 -- levels are exceeded in the
wash/rinse solution. The compositions of the invention are hence most
likely to be beneficial when used in rinse solutions in which said
threshold limits have been exceeded.
In particular calcium carbonate deposit formation is likely to be a problem
when the CO.sub.3.sup.2+ /HCO.sub.3 -- level in the rinse solution exceeds
8.degree. German hardness, and when the Ca.sup.2+ /Mg.sup.2+ level in the
rinse solution exceeds 6.degree. (3:1 Ca:Mg) German hardness (equivalent
to 1.08 mmol Ca.sup.2+ /liter).
EXAMPLES
The following examples illustrate the present invention.
In the following compositions, the abbreviated identifications have the
following meanings:
Citric : Citric acid
Nonionic: C.sub.13 -C.sub.15 mixed ethoxylated/propoxylated fatty alcohol
with an average degree of ethoxylation of 3.8 and an average degree of
propoxylation of 4.5 sold under the tradename Plurafac LF404 by BASF Gmbh.
HEDP : Ethane 1-hydroxy-1,1-diphosphonic acid
DETPMP : Diethylene triamine penta (methylene phosphonic acid), marketed by
Monsanto under the tradename Dequest 2060
EDDS : Ethylenediamine-N, N'-disuccinic acid ›S,S! isomer
AA/MA: Random copolymers of acrylic acid and methacrylic acid in a weight
ratio of approximately 30:70, with a molecular weight of about 3,500
Polyacrylate: A polyacrylate homopolymer with an average molecular weight
of 8,000 sold under the tradename PA30 by BASF GmbH
SCS: Sodium cumene sulfonate
Citrate: Trisodium citrate dihydrate
MA/AA: Copolymers of 1:4 maleic/acrylic acid, average molecular weight
about 80,000
Protease: Proteolytic enzyme sold under the trade name Savinase by Novo
Industries A/S
Amylase: Amylolytic enzyme sold under the trade name Termamyl by Novo
Industries A/S
Silicate: Sodium silicate (2.0 ratio)
PB1: Sodium perborate monohydrate
PB4: Sodium perborate tetrahydrate
TAED: Tetraacetyl/ethylene diamine
Paraffin: Paraffin oil, sold under the tradename Winog 70 by Wintershall
Example 1
The following liquid rinse aid compositions were prepared (parts by
weight).
______________________________________
A B C D E F
______________________________________
Citric 6.5 6.5 6.5 6.5 6.5 6.5
Nonionic 12.0 12.0 12.0 12.0 12.0 12.0
HEDP -- 5.0 2.5 5.0 5.0 5.0
DETPMP -- -- 3.0 -- -- --
EDDS -- -- -- 3.0 -- --
Polyacrylate -- -- -- -- 5.0 --
AA/MA -- -- -- -- -- 5.0
SCS 4.8 4.8 4.8 4.8 4.8 4.8
Ethanol 6.0 6.0 6.0 6.0 6.0 6.0
Ammonia 0.7 0.7 -- 0.7 0.7 0.7
Water/misc to balance
3.3 3.3 2.4 3.3 3.3 3.3
pH 1% solution
______________________________________
Composition A is a prior art composition. Compositions B to F are in accord
with the invention.
Calcium carbonate deposition evaluation
The tendency to form CaCO.sub.3 deposits when used in a machine
dishwashing/rinsing method of Composition B, which is in accord with the
invention was compared to that of the prior art Composition A using the
following test protocol:
A full set of dinnerware (12 dinner plates, 6 side plates, 12 saucers, 6
glasses, 8 tea cups, 16 stainless steel spoons, 4 silver spoons) was
placed in a Bosch Siemens SMS 9022 (tradename) automatic dishwasher. 25g
of detergent product (Composition I, formulation given below) was placed
in the machine detergent dispenser, and 3 g of the test rinse aid product
added to the rinse aid dispenser. The 65.degree. C. cycle was selected.
Subsequent to each admission of water, of known hardness, to the main
cavity of the machine a volume of sodium bicarbonate was added to the
water to provide a 30.degree. German hardness level of
carbonate/bicarbonate ions and 8.degree. German harness levels (3:1 Ca:Mg)
of Ca.sup.2+ /Mg.sup.2+ ions (equivalent to 1.44 mmol Ca.sup.2+ /liter) in
the wash/rinse solution. Subequent to the dispensing of the detergent to
the wash solution 50 g of a representative liquid soil (comprising
approximately 1.9% tomato ketchup, 1.9% mustard, 2% egg yolks, 39% milk,
0.6% benzoic acid, 1.9% (dissolved) gravy granules, 3.8% potato, water to
balance) was added to the wash solution. This procedure was repeated until
8 complete machine cycles (each comprising prewash, wash, 2 rinses) had
been completed (rinse aid is only added to the final rinse).
Results
After 8 complete cycles the machine was stopped and the machine parts and
dinnerware were assessed for deposit formation using the following visual
scale:
0=no deposits
1=slight deposits
2=significant/heavy deposits
The following results were obtained.
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Composition
Substrate A B
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Glassware 1 1
Chinaware 2 0
Silverware 2 1
Stainless 2 0
steel
Machine 2 0
door
Machine 2 1
heater
element
Machine 2 0
spray arm
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The MEDP containing formulation (composition B) is seen to give rise to
only minor deposit formation. Composition A, by contrast gives rise to
significant deposits.
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Detergent formulation employed in test protocol
I
______________________________________
Citrate 29.0
MA/AA 3.7
Silicate 25.7
PB1 1.9
PB4 8.7
TAED 4.4
Protease 2.2
Amylase 1.5
Benzotriazole
0.3
Paraffin 0.5
Nonionic 1.5
DETPMP 0.1
Misc/moisture to
balance
pH (1% solution)
10.7
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